根據對話內容，從下面方框中選擇適當的單詞填空，使對話內容完整正確。
Reporter：Can you introduce something about your latest class activity?
Monitor：Sure. The students from our class planted some lines of trees on March 12
th, 2008.
Reporter：How did you plant trees?
Monitor：First, the students were
小題1:
into groups of four. Next, each group of students planted a tree. Then, they poured some water over the trees.
Reported：How do you
小題2:
for the trees?
Monitor： We plan to come back and look after the trees
小題3:
.
Reported：Sounds good. Could you tell me why you choose to do that?
Monitor：As you know, pollution has become one of the most serious
小題4:
. We would like to try our best to improve our environment.
Reporter：Well, it’s very meaningful. If everyone can do something to protect the environment
小題5:
, our city will become much more beautiful.
